A method of replicating the surfaces of wet whole cells has been devised. This consists of placing the preparation (cells grown on gold electron microscope specimen grids) in an atmosphere of water vapor in a differentially pumped hydration chamber inside a vacuum evaporator. Silicon monoxide is evaporated through small apertures on to the wet surfaces of the cells to form a replica. The optimum conditions for the replication have been worked out and preliminary results have been obtained on wet objects.